When adventuring, your expendable resources have a hierarchy of value.
Based on my experience, here they are, from least to most value:
In short, spend money to avoid spending magic, spend magic to avoid spending HP, and spend
HP only when you have to.
Mundane resources include money, and anything you can buy with it (and easily replace). Arrows, holy water, healing potions, thrown weapons, etc. In a vicious enough game, this could be hirelings, too. But generally, hirelings aren't so disposable either because of roleplaying concerns (Sense of Duty, say, or alignment in DnD) or pragmatic concerns (they're hard to replace if you spend them like bullets as no one wants to hire on with you).
Magic resources include spells in Vancian magic systems, energy and power item points and paut in GURPS Dungeon Fantasy, spell points in Rolemaster, and any and all magical item charges and one-shot items. Some of these are easily recovered, some aren't, but ultimately they come with a cost that's generally higher than bribe money or pre-purchased mundane expendables. Even if you can get magical energy back fast (like in GURPS) the time you spend doing it in the dungeon is time you are in danger.
HP is obvious. HP, life force, body points, actual lives. If you die, generally you can fix it, but it's inconvenient at best and hideously expensive at worst.
The trick to this one is that treasure is the goal, so ultimately you will "spend" HP to get GP. But the ideal is to get as much treasure at as little cost as possible. If you toss a $100 hostile potion down the gullet of a monster and loot it of $500 in treasure, that's fine. If you expend it and get $0, maybe it's okay, too, because the only other way to beat it might have cost a bunch of magical energy and HP. This is why wandering monsters and dead-end encounters aren't worth fighting - do you need to spend resources to whack a destitute and dangerous critter?
The scale will slide a bit, too - it's probably better to expend a couple HP than a few thousand gold coins. Or burn up an awesome magic item to kill a corrosive slugbeast before it eats your cheap but necessary 10' pole. But writing up a sliding scale of value with overlapping categories is too much like work.
Anyway, I find this hierarchy useful. The goal is always loot, but how much do you spend to get it? What's a better trade, some damage or some expendables? A spell or the mundane?
Ultimately every experienced players knows this, but probably doesn't put it explicitly in this order.
Does your hierarchy of expendables differ?